KR101375193B1 - Capacitance sensor - Google Patents

Abstract

An object of the present invention is to provide a capacitive sensor capable of reducing power consumption and capable of intermittent operation.
A capacitive sensor 1 capable of detecting a first capacitance and a second capacitance, the first member having a conductive diaphragm 11 and a diaphragm 11 formed therebetween. A space S1 is formed between the thin film electrode 21 forming the capacitance and the thin film electrode 31 forming the second capacitance between the diaphragm 11 and the upper surface of the diaphragm 11. And a lower member 30 provided to form a space S2 between the upper member 20 installed so as to form a space S2 and a lower surface of the diaphragm 11, and the gas A1 is enclosed in the space S1. In the space S2, a gas A2 having a different thermal expansion coefficient from the gas A1 is sealed.

Description

Capacitive Sensors {CAPACITANCE SENSOR}

Some aspects according to the invention relate to a capacitive sensor capable of detecting temperature, for example.

BACKGROUND ART Conventionally, an electric thermometer using a platinum resistor, a thermocouple, a semiconductor temperature sensor, or the like is provided with a temperature detector having two different metal materials different from each other and a protective tube for protecting them, and twisted pairing the two metal materials. It is known that the noise resistance was improved by making a coaxial cable (for example, refer patent document 1).

Japanese Patent Application Laid-open No. Hei 8-86694

In order to prevent the disturbance of the electric thermometer, the temperature detector is covered by a protective tube or a package. Therefore, the time until the temperature detection unit reaches the same temperature as the temperature measurement object (hereinafter, the time until reaching 63.2% of the temperature measurement object is referred to as the "response time", and the time until reaching 90% is " Stable time ”), depending on the kind of long time and kind, for example, several seconds to several minutes. Therefore, since the response time (stable time) is required after the energization, it is not suitable for the so-called intermittent operation of energizing (operating) at the time of temperature measurement and stopping after the temperature measurement.

Conventionally, in order to cope with such a situation, the electric thermometer was always energized (the electric energy was always supplied to the electric thermometer) so that the temperature could be measured immediately at the time of temperature measurement. However, such a method consumes power in addition to the temperature measurement, and therefore, it has been difficult to reduce power consumption. That is, there is a problem that the power consumption cannot be reduced and the intermittent operation for reducing the power consumption cannot be performed.

Some aspects of the present invention have been made in view of the above problems, and an object thereof is to provide a capacitive sensor capable of reducing power consumption and intermittent operation.

The capacitive sensor according to the present invention is a capacitive sensor capable of detecting a first capacitance and a second capacitance, the first sensor having a conductive electrode plate formed thereon and a first electrode formed between the electrode plate and the electrode plate. A second member provided to form a first space between the first electrode forming the first capacitance, the second electrode forming the second capacitance between the electrode plate, and one side of the electrode plate; And a third member provided to form a second space between the other surface of the electrode plate, the first gas being enclosed in the first space, and having a different thermal expansion coefficient from the first gas in the second space. 2 gases are sealed.

According to this structure, a 1st gas is enclosed in a 1st space, and the 2nd gas from which a thermal expansion coefficient differs from a 1st gas is enclosed in a 2nd space. Here, in the case where the first gas and the second gas having different thermal expansion coefficients are enclosed in the first space and the second space, respectively, when the temperature measurement object, for example, the outside air temperature changes, the internal first gas and the second gas are changed. The temperature of the gas also changes. At this time, a pressure difference occurs between the pressure in the first space and the pressure in the second space due to the difference in thermal expansion coefficient between the first gas and the second gas. The electrode plate disposed between the first space and the second space is displaced according to this pressure difference, so that the first capacitance and the second capacitance change. Therefore, by detecting the first capacitance and the second capacitance, it becomes possible to measure the temperature of the temperature measurement object. In addition, since the electrode plate is displaced according to the temperature change of the temperature measurement target without energizing, it is possible to immediately detect the first capacitance and the second capacitance at the time of energization. In addition, since the impedance (capacitance reactance) is increased by applying a low frequency alternating voltage to two spaced apart electrodes forming a capacitance, that is, a capacitor (capacitor), it is possible to reduce the current flowing at the time of energization.

Moreover, the capacitive sensor which concerns on this invention is a capacitive sensor which can detect a 1st capacitance and a 2nd capacitance, Comprising: The 1st member in which the movable electrode plate which has electroconductivity was formed, and an electrode plate are provided. A second member provided to form a first space between the first electrode to form the first capacitance, the second electrode to form the second capacitance, and one side of the electrode plate, and the electrode plate. And a third member provided to form a second space between the other surface of the first space, the first gas being enclosed in the first space, and the second gas having a different thermal expansion coefficient from the first gas in the second space. It is enclosed.

Preferably, the first member is conductive and an electrode portion is formed to form a second capacitance with the second electrode.

Preferably, a third electrode is further provided to form a second capacitance with the second electrode.

Preferably, further comprising a fourth member having conductivity and provided with an electrode portion for forming the second capacitance between the second electrode and the second electrode.

Preferably, the electrode plate has a mesa shape on the surface of the first substrate and the second substrate facing the space in which the substrate having the high thermal expansion coefficient is sealed.

Preferably, the first member includes a first conductive layer on which the electrode plate is formed, a second conductive layer, and an insulating layer interposed between the first conductive layer and the second conductive layer.

Preferably, the first member includes a first conductive layer on which an electrode plate is formed, a second conductive layer on which a second electrode is formed, and an insulating layer interposed between the first conductive layer and the second conductive layer. .

Preferably, a 3rd space which accommodates a getter material and communicates with a 1st space is formed in a 1st member, and a 1st gas is a vacuum state.

According to the capacitance type sensor which concerns on this invention, it becomes possible to measure the temperature of a temperature measurement object by detecting a 1st capacitance and a 2nd capacitance. In addition, since the electrode plate is displaced according to the temperature change of the temperature measurement target without energizing, it is possible to immediately detect the first capacitance and the second capacitance at the time of energization. In addition, since the impedance (capacitance reactance) is increased by applying a low frequency alternating voltage to two spaced apart electrodes forming a capacitance, that is, a capacitor (capacitor), it is possible to reduce the current flowing at the time of energization. As a result, the temperature can be measured without always supplying electrical energy, and power consumption can be reduced. In addition, the response time (stable time) can be significantly shortened, thereby enabling intermittent operation.

1 is a side cross-sectional view of a capacitive sensor in a first embodiment of the present invention.
FIG. 2 is a plan view illustrating the shape of the diaphragm shown in FIG. 1.
3 is a view for explaining the capacitance detected by the capacitive sensor shown in FIG. 1.
4 is a graph illustrating a relationship between temperature and pressure of a gas enclosed in a sealed space.
5 is a graph for explaining the relationship between the temperature of the gas enclosed in the sealed space and the displacement of the diaphragm.
6 is a side cross-sectional view of a capacitive sensor in a second embodiment of the present invention.
It is a figure explaining the capacitance which the capacitive sensor shown in FIG. 6 detects.
8 is a side cross-sectional view showing another example of the capacitive sensor in the second embodiment of the present invention.
9 is a side cross-sectional view showing another example of the capacitive sensor in the second embodiment of the present invention.
10 is a side cross-sectional view showing a capacitive sensor in a modification of the second embodiment of the present invention.
11 is a side cross-sectional view showing another example of the capacitive sensor in the modification of the second embodiment of the present invention.
It is a side sectional view of the capacitive sensor in 3rd Embodiment of this invention.
It is a top view explaining the shape of the diaphragm shown in FIG.
14 is a side cross-sectional view showing another example of the capacitive sensor in the third embodiment of the present invention.
15 is a side cross-sectional view of a capacitive sensor in a fourth embodiment of the present invention.
FIG. 16 is a plan view of the electrode unit illustrated in FIG. 15.
17 is a side cross-sectional view showing another example of the capacitive sensor in the fourth embodiment of the present invention.
It is a side sectional view of the capacitive sensor in 5th Embodiment of this invention.
19 is a side cross-sectional view showing another example of the capacitive sensor in the fifth embodiment of the present invention.
20 is a side cross-sectional view showing another example of the capacitive sensor in the fifth embodiment of the present invention.
21 is a side cross-sectional view showing another example of the capacitive sensor in the fifth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. In addition, of course, the part from which the relationship and the ratio of a mutual dimension differ also in between drawings is contained.

(First embodiment)

1 to 5 illustrate the first embodiment of the capacitive sensor according to the present invention. 1 is a side cross-sectional view of a capacitive sensor in a first embodiment of the present invention, FIG. 2 is a plan view for explaining the shape of the diaphragm shown in FIG. 1, and FIG. 3 is a capacitive sensor shown in FIG. 1. It is a figure explaining the electrostatic capacitance to detect. In addition, the X-axis, Y-axis, and Z-axis shown in FIG.1 and FIG.2 are the coordinate axes orthogonal to each other, a Y-axis is orthogonal to a horizontal direction with respect to an X-axis, and a Z-axis is orthogonal to a perpendicular direction with respect to an X-axis. The same also applies to the subsequent drawings. In addition, in the following description, the upper side of the figure is shown as the upper side, the lower side, the left side, and the right side.

As shown in FIG. 1, the capacitive sensor 1 is for measuring the temperature of the temperature measurement object, such as an external environment, for example, the ambient air | atmosphere. The capacitive sensor 1 includes a conductive member 10, an upper member 20 provided above the member 10, and a lower member 30 provided below the member 10.

The member 10 is composed of, for example, conductive single crystal silicon (low resistance silicon). The diaphragm 11 which is displaceable in the predetermined direction (Z-axis direction in FIG. 1) is formed in the member 10. As shown in FIG. As shown in FIG. 2, the diaphragm 11 has a long length direction (long side, an X-axis direction in FIG. 2) having a length L and a short length direction (short side, a Y-axis in FIG. 2) as viewed in a plan view. Direction) has a rectangular shape of length W. The diaphragm 11 functions as a movable electrode plate whose thickness (length in the Z-axis direction in FIG. 1) is thinner than the member 10.

The upper and lower surfaces of the diaphragm 11 are not limited to the flat (flat) shape as shown in FIG. 1, and at least one surface may have a corrugated shape. The shape of the diaphragm 11 in plan view is not limited to the rectangle shown in FIG. 2, but may be square, polygonal, circular, elliptical, or the like.

As shown in FIG. 1, thin film-shaped protrusions 11a and 11b each having electrical insulation are formed on the upper and lower surfaces of the diaphragm 11. Thereby, it can electrically insulate with the thin film electrodes 21 and 31 mentioned later, or sticking (sticking) can be prevented.

The upper member 20 is comprised from ceramics, for example. The lower surface of the upper member 20 is joined to the upper surface of the member 10 so as to form a closed space S1 between the upper surface of the diaphragm 11. Moreover, the thin film electrode 21 is provided in the lower surface of the upper member 20 in the position which opposes the diaphragm 11. As shown in FIG. 3, the thin film electrode 21 is spaced apart from the diaphragm 11 by an interval d _A1 , and forms a capacitance C ₁ between the diaphragm 11. The thin film electrode 21 and the diaphragm 11 function as a capacitor (capacitor).

As shown in FIG. 1, the lower member 30 is comprised from ceramics, for example. The upper surface of the lower member 30 is joined to the lower surface of the member 10 so as to form a closed space S2 between the lower surface of the diaphragm 11. Moreover, the thin film electrode 31 is provided in the upper surface of the lower member 30 in the position which opposes the diaphragm 11. As shown in FIG. 3, the thin film electrode 31 is spaced apart from the diaphragm 11 by an interval d _A2 , and forms a capacitance C ₂ between the diaphragm 11. The thin film electrode 31 and the diaphragm 11 function as a capacitor (capacitor).

The joining of the member 10 and the upper member 20 or the lower member 30 is performed using, for example, mechanical joining, direct joining, or anodic joining in consideration of the airtightness of the spaces S1 and S2. .

The material of the upper member 20 and the lower member 30 is not limited to ceramics, At least one is boric acid type glass (alkaline glass), quartz, quartz, or sapphire, and may be joined by the above-mentioned joining method. Specifically, in the case of anodic bonding, pyrex (registered trademark) glass, tempax, SD2 glass, SW-Y, SW-YY glass, or low temperature co-fired ceramics (LTCC) may be used. As the material of the upper member 20 and the lower member 30, conductive silicon or a metal may be used for at least one of the members, similar to the member 10. In this case, it is bonded to the member 10 with an insulating film interposed therebetween. In addition, as a material of the upper member 20 and the lower member 30, a crystal or a polycrystal having at least one conductive thin film electrode and capable of forming a capacitance between the diaphragm 11 can be used. good.

As shown in FIG. 1, the left end part of the thin film electrode 21 is connected to the conductive feedthrough hole electrode H1. The feed-through hole electrode H1 is electrically connected to an electrode pad (terminal) P1 provided on the upper surface of the upper member 20. The right end of the diaphragm 11 is connected to the conductive portion 12 constituting a part of the member 10. The conductive portion 12 is electrically connected to the diaphragm pad (terminal) P2 provided on the upper surface of the upper member 20 through the conductive feedthrough hole electrode H2. The right end of the thin film electrode 31 is connected to the silicon island 13 constituting a part of the member 10. The silicon island 13 is electrically connected to the electrode pad (terminal) P3 provided on the upper surface of the upper member 20 through the conductive feed-through hole electrode H3.

The capacitance C ₁ can be detected by, for example, applying an alternating voltage having a predetermined frequency to the electrode pad P1 and the diaphragm pad P2 and measuring a current flowing at the time of application. The capacitance C ₂ can be detected by, for example, applying an alternating voltage having a predetermined frequency to the electrode pad P3 and the diaphragm pad P2 and measuring a current flowing at the time of application.

The feed-through hole electrodes H1 to H3 are formed by forming through holes (not shown) in the upper member 20, respectively, and embedding the electrode material into a film, plating, or embedding wiring. .

The conductive portions 12 and the silicon islands 13 are formed by a chemical reactive etching method in a gas phase such as dry etching, a water-soluble chemical etching method, or the like. In addition, the formation of the diaphragm 11 is performed by controlling the thickness in accordance with the etching time using a water-soluble chemical etching method, or by performing selective etching by diffusing a high concentration of impurities at a position on the member 10 corresponding to the diaphragm. All.

A gas A1, for example a gas in a vacuum state, is enclosed in the space S1, and a gas A2, for example, an inert gas, having a different thermal expansion coefficient from the gas enclosed in the space S1 is enclosed in the space S2. .

In this application, a "vacuum state" does not mean a state in which there is nothing, but means a state (negative pressure) whose pressure is lower than atmospheric pressure. Therefore, even if any space is in a vacuum state, a substance (a gas in this application) is present, and therefore, a gas present in this space is referred to as a "vacuum gas".

In addition, the combination of the gas enclosed in space S1 and the gas enclosed in space S2 is not limited to the above-mentioned thing, A thermal expansion rate, more precisely, a volume expansion rate may mutually differ. For example, the gas A1 may be a first inert gas, and the gas A2 may be a second inert gas or dry air. However, when the temperature is low, condensation occurs in the gas with high humidity, and the influence on the volume change of the gas to be described later is large. Therefore, gas which is hard to condense, such as a vacuum gas, an inert gas, dry air, is preferable.

Here, in the case where the gas A1 and the gas A2 having different thermal expansion coefficients are respectively enclosed in the sealed space S1 and the space S2, when the temperature measurement object, for example, the outside air temperature changes, The temperature of the gas A1 and the gas A2 also changes. At this time, a pressure difference occurs between the pressure in the space S1 and the pressure in the space S2 due to the difference in thermal expansion coefficient between the gas A1 and the gas A2. The diaphragm 11 disposed between the space S1 and the space S2 is displaced according to this pressure difference, and the capacitance C ₁ and the capacitance C ₂ change. Therefore, by detecting the capacitance C ₁ and the capacitance C ₂ , the temperature of the temperature measurement target can be measured. In addition, since the diaphragm 11 is displaced according to the temperature change of the temperature measurement object without energizing, it becomes possible to detect the capacitance C ₁ and the capacitance C ₂ immediately at the time of energization. In addition, since the impedance (capacitance reactance) is increased by applying a low frequency alternating voltage to two spaced apart electrodes forming a capacitance, that is, a capacitor (capacitor), it is possible to reduce the current flowing at the time of energization.

Background Art Conventionally, glass thermometers, liquid column thermometers, metal thermometers, and bimetal thermometers have been known as thermometers capable of reducing power consumption. Since a glass thermometer and a liquid column thermometer utilize the thermal expansion property of the material according to the temperature change of a temperature measurement object, it can measure temperature, without requiring electrical energy like an electric thermometer. However, since the measured temperature is read by visually confirming the scale as a rule, it is difficult to convert into an electrical signal and to accurately measure the temperature. In addition, it is also possible to attach an image sensor and a signal processing circuit to convert the temperature of the scale into an electrical signal, but there is a risk of causing an increase in cost and power consumption. On the other hand, metal thermometers and bimetallic thermometers can easily convert measured temperatures into electrical signals. However, in order to maintain the sensitivity to temperature, since the detection unit is exposed, it is susceptible to disturbances such as humidity, vibration, dust, dust, and the like.

In contrast, the capacitive sensor 1 according to the present invention can be easily converted into an electrical signal of temperature by detecting the capacitance C ₁ and the capacitance C ₂ . In addition, since the gas A1 and the gas A2 are respectively enclosed in the sealed space S1 and the space S2, the gas A1 and the gas A2 have the advantage of being less susceptible to disturbance.

Next, the relationship between the temperature change of the temperature measurement object and the capacitance change of the capacitive sensor will be described in detail with reference to FIGS. 4 to 6. In addition, unless otherwise indicated, gas A1 is demonstrated as a vacuum gas, and gas A2 is described as an inert gas.

4 is a graph illustrating a relationship between temperature and pressure of a gas enclosed in a sealed space. In general, when a gas is enclosed in an enclosed space having a predetermined volume, the behavior (behavior, operation) of the gas can be expressed by using the state equation of the ideal gas. That is, the volume of the absolute zero (absolute temperature) v _0, when assuming that the pressure p _0, the pressure at the predetermined temperature t ₁ p ₁ And the volume v ₁ satisfy the following relationship between the formulas (1) and (2).

p ₁ v ₁ = p ₀ v ₀ (1 + β t ₁ ). (One)

v ₁ = v ₀ (1 + gt ₁ ) ... (2)

However, β represents the volume expansion rate of the gas, and g represents the volume expansion rate of the sealing material sealing the space.

Similarly, the pressure at the temperature t ₂ of the other fixed p ₂ And the volume v ₂ satisfy the following expressions (3) and (4).

p ₂ v ₂ = p ₀ v ₀ (1 + β t ₂ ). (3)

v ₂ = v ₀ (1 + gt ₂ ). (4)

Here, when the temperature of the gas enclosed in the enclosed space changes from t ₁ to t ₂ , the pressure p ₂ after the temperature change is summarized by the following formulas (1) to (4) and represented by the following formula (5). Can be.

p ₂ = {(1 + βt ₂ ) / (1 + βt ₁ )} {(1 + gt ₁ ) / (1 + gt ₂ )} × p ₁ . (5)

When the pressure p ₂ is calculated using Equation (5), as shown in FIG. 4, it can be seen that the relationship between the temperature of the gas enclosed in the sealed space and the pressure is a linear relationship.

5 is a graph for explaining the relationship between the temperature of the gas enclosed in the sealed space and the displacement of the diaphragm. A literature: According to (Stephen P. Timoshenko, S. Woinowsky- Krieger, "Theory Of Plates and Shells", New-York. McGRAW-HILL , Inc., 2 nd Edition), usually fixed around, when viewed in plane In the case of diaphragm having a rectangular shape, the displacement w (x, y) in the vertical direction (e.g., Z-axis direction in FIG. By the following formulas (6) and (7).

Where a is the length of the short side of the diaphragm, b is the length of the long side of the diaphragm, D is a function representing the elastic properties of the diaphragm (flexural rigidity), A _m , B _m , C _m are shape constants, and E is the diaphragm The Young's modulus of the material, h is the thickness of the diaphragm, and v is the Poisson's ratio of the diaphragm material.

In addition, when the shape of the diaphragm in plan view is other than a rectangle, by changing Formula (6), the displacement w (x, y) can be expressed similarly using the pressure p applied to the diaphragm.

Here, the above-described theory is considered to be applied to the present invention. That is, assuming that the maximum displacement of the diaphragm 11 at the temperature t ₁ is d ₁ , and the temperature of the gas enclosed in the closed space is changed from t ₁ to t ₂ , the gas A1 is a gas in a vacuum state. For this reason, the pressure in the space S1 is invariant (or substantially invariant). Therefore, the pressure applied to the diaphragm 11 is only the pressure of the space S2. At this time, the maximum displacement d ₂ of the diaphragm 11 can be calculated by substituting p ₂ of the formula (5) for the pressure p in the formula (6). As shown in FIG. 5, it can be seen that the relationship between the temperature of the gas A2 and the displacement of the diaphragm 11 is also a linear relationship.

In addition, when gas A1 enclosed in space S1 changes in pressure according to temperature change, for example, inert gas, about space S1, Formula (1) '-Formula (4) similarly to the above-mentioned. Since '' holds, equation (5) 'is derived from these equations. Here, formulas (1) 'to (4)' and formula (5) 'denote the β (volume expansion rate of the gas) and g (the sealing material in the above formulas (1) to (4) and (5). (Volume expansion coefficient of) changes, so that the gas changes in pressure as the temperature changes. By calculating formulas (5)-(5) '(= Δp) and substituting the calculated Δp into the pressure p in formula (6), the maximum displacement d ₂ of the diaphragm 11 can be calculated in a similar manner.

The capacitance C when the electrode is movable displaced in the vertical direction can be expressed by the following equation (8) using the displacement w (x, y) of the diaphragm 11.

However, C ₀ represents the capacitance at a predetermined temperature (initial temperature), ε ₀ represents the dielectric constant in vacuum, and d represents the distance between electrodes in the initial state.

In addition, the capacitance change (ΔC) of the capacitive sensor 1 can be defined by the following equation (9).

ΔC = (C ₁ -C ₂ ) / C ₂ . (9)

Therefore, by substituting Eq. (6) into the displacement w (x, y) in Eq. (8) and calculating Eq. (9), the capacitance change ΔC of the capacitive sensor 1 is converted into a temperature ( As a function of temperature). The capacitance change ΔC can be linear with respect to temperature by the correction method even if there is a variation in the sensor or the manufacturing process with respect to the temperature change, and has a nonlinear characteristic.

In this embodiment, although the thing which has electroconductivity was used as a material of the member 10, it is not limited to this. For example, a thin film of a conductive material may be formed on the upper and lower surfaces (both surfaces) of the diaphragm 11 using an insulating material. In this case, the conductive portion 12 and the silicon island 13 are similarly formed of a conductive material.

As described above, according to the capacitive sensor 1 of the present embodiment, the gas A1 is sealed in the space S1, and the gas A2 having a different thermal expansion coefficient from the gas A1 is sealed in the space S2. do. Here, in the case where the gas A1 and the gas A2 having different thermal expansion coefficients are respectively enclosed in the sealed space S1 and the space S2, when the temperature measurement object, for example, the outside air temperature changes, The temperature of the gas A1 and the gas A2 also changes. At this time, a pressure difference occurs between the pressure in the space S1 and the pressure in the space S2 due to the difference in thermal expansion coefficient between the gas A1 and the gas A2. The diaphragm 11 disposed between the space S1 and the space S2 is displaced according to this pressure difference, and the capacitance C ₁ and the capacitance C ₂ change. Therefore, by detecting the capacitance C ₁ and the capacitance C ₂ , the temperature of the temperature measurement target can be measured. In addition, since the diaphragm 11 is displaced according to the temperature change of the temperature measurement object without energizing, it becomes possible to detect the capacitance C ₁ and the capacitance C ₂ immediately at the time of energization. In addition, since the impedance (capacitance reactance) is increased by applying an alternating voltage of low frequency, the two electrodes spaced apart, i.e., capacitors (capacitors), which form a capacitance, can reduce the current flowing during energization. As a result, the temperature can be measured without always supplying electrical energy, and power consumption can be reduced. In addition, the response time (stable time) can be significantly shortened, thereby enabling intermittent operation.

(Second Embodiment)

6 to 9 are for describing the second embodiment of the capacitive sensor according to the present invention. In addition, unless otherwise indicated, the same structural part as 1st Embodiment mentioned above is represented by the same code | symbol, and the description is abbreviate | omitted. In addition, the component part which is not shown in figure is made the same as that of 1st Embodiment mentioned above.

The difference between the second embodiment and the first embodiment is that the capacitive sensors 2A, 2B, and 2C include the reference electrode 22 instead of the thin film electrode 31.

FIG. 6 is a side cross-sectional view of the capacitive sensor in the second embodiment of the present invention, and FIG. 7 is a diagram for explaining the capacitance detected by the capacitive sensor shown in FIG. 6. As shown in FIG. 6, in the member 10, a fixing portion 14 is formed at the right end of the diaphragm 11 instead of the conductive portion 12. While the diaphragm 11 can be displaced in a predetermined direction (Z-axis direction in FIG. 6), the fixing portion 14 is not displaceable (floating) in at least this predetermined direction (Z-axis direction in FIG. 6).

On the upper surface of the fixing portion 14, a thin projection 11c having electrical insulation is formed. Thereby, it can electrically insulate with the reference electrode 22 mentioned later, or sticking (sticking) can be prevented.

On the lower surface of the upper member 20, a thin film type reference electrode 22 is provided at a position opposite to the fixing portion 14 along with the thin film electrode 21. As shown in FIG. 7, the reference electrode 22 is spaced apart from the fixed portion 14 by an interval d _A1 , and forms a capacitance C ₃ between the fixed portion 14 and the fixed portion 14. The reference electrode 22 and the fixing portion 14 function as a capacitor (capacitor).

As shown in FIG. 6, the left end of the diaphragm 11 is connected with the part (not shown) which comprises a part of member 10. As shown in FIG. This part is electrically connected to the diaphragm pad (terminal) P2 via the feed-through hole electrode H2. The right end of the reference electrode 22 is connected to the feed through hole electrode H3. The feed-through hole electrode H3 is electrically connected to the pad (terminal) P3 for thin film electrodes.

The capacitance change ΔC of the capacitive sensor 2A can be defined by the following equation (9) '.

ΔC = (C ₁ -C ₃ ) / C ₃ . (9) '

Here, as in the first embodiment, when a pressure difference occurs between the pressure in the space S1 and the pressure in the space S2, the diaphragm 11 is displaced according to the pressure difference, while the fixing portion 14 It does not displace even if pressure difference occurs. Therefore, since the capacitance C ₁ changes with respect to the temperature change but the capacitance C ₃ does not change, the capacitance change ΔC of the capacitive sensor 2A is obtained from the equation (9) '. It is a change of (C ₁ ).

8 is a side cross-sectional view showing another example of the capacitive sensor in the second embodiment of the present invention. In the present embodiment, but so as to form a capacitance (C ₃₎ between the diaphragm and the right edge (14) and fixing (14) form a state of 11, the invention is not limited to this. For example, as shown in FIG. 8, the capacitive sensor 2B may form another diaphragm 17 electrically insulated from the diaphragm 11 in the member 10. In this case, a thin film-like protrusion 17a having electrical insulation is formed on the upper surface of the diaphragm 17. The lower surface of the upper member 20 is provided with a reference electrode 22 at a position opposite to the upper surface of the diaphragm 17. The reference electrode 22 forms a capacitance C ₃ between the upper surface of the diaphragm 17. The upper surface of the reference electrode 22 and the diaphragm 17 functions as a capacitor (capacitor). The right end of the diaphragm 17 is connected with a part (not shown) which comprises a part of the member 10. This part is electrically connected to the diaphragm pad (terminal) P4 via the feed-through hole electrode H4. The reference electrode 22 is connected to the feed through hole electrode H3. The feed-through hole electrode H3 is electrically connected to the pad (terminal) P3 for thin film electrodes.

The gas A2 is sealed in the space S4 formed between the lower surface of the upper member 20 and the upper surface of the diaphragm 17 and sealed. In the space S5 formed between the upper surface of the lower member 30 and the lower surface of the diaphragm 17, the same gas as the space S4, for example, gas A2, is enclosed.

Here, when the temperature measurement object, for example, the outside air temperature changes, since the gas with the same thermal expansion coefficient is enclosed in the space S4 and the space S5, the pressure of the space S4 and the pressure of the space S5 are sealed. There is no pressure difference between them. Therefore, as in the case shown in FIG. 6, since the capacitance C ₁ changes with respect to the temperature change but the capacitance C ₃ does not change, the capacitance change ΔC of the capacitive sensor 2B is changed. Is the change in capacitance C ₁ from equation (9) '.

In addition, the electrode which forms the capacitance C ₃ between the reference electrode 22 is not limited to the diaphragm 17, and may be a fixed electrode (part) formed in the member 10, and other than the member 10. It may be formed in the member. The gas encapsulated in the space S4 and the space S5 is preferably an inert gas, but the gas A2 is preferably used. However, the gas A2 or other gas may be used.

9 is a side cross-sectional view showing another example of the capacitive sensor in the second embodiment of the present invention. As shown in FIG. 9, the capacitive sensor 2C faces the reference electrode 22 provided on the lower surface of the upper member 20 and the reference electrode 22 on the upper surface of the lower member 30. The reference electrode 34 of the thin film type provided in the position to be provided may be provided. The reference electrode 34 forms a capacitance C ₃ between the reference electrode 22 and the reference electrode 22. The reference electrode 22 and the reference electrode 34 function as a capacitor (capacitor). The reference electrode 34 is connected to the feed through hole electrode H4. The feed-through hole electrode H4 is electrically connected to the pad (terminal) P4 for diaphragm. The reference electrode 22 is connected to the feed through hole electrode H3. The feed-through hole electrode H3 is electrically connected to the pad (terminal) P3 for thin film electrodes.

The gas A2 is sealed in the space S4 formed between the lower surface of the upper member 20 and the upper surface of the lower member 30 and sealed.

Here, since the reference electrode 22 and the reference electrode 34 are fixed when the temperature measurement object, for example, the external atmospheric temperature changes, the capacitance C with respect to the temperature change as in the case shown in FIG. ₁ ) changes but the capacitance C ₃ does not change. Therefore, the change in capacitance ΔC of the capacitive sensor 2C becomes the change in capacitance C ₁ from equation (9) '.

The gas encapsulated in the space S4 is preferably an inert gas in the same manner as shown in FIG. 8, but may be a gas A1 or another gas.

As described above, according to the capacitive sensors 2A, 2B, and 2C of the present embodiment, the reference electrode 22 for forming the capacitance C ₃ is provided. Here, as in the first embodiment, when a pressure difference occurs between the pressure in the space S1 and the pressure in the space S2, the diaphragm 11 is displaced according to the pressure difference, while the fixing portion 14 is, for example, It does not displace even if the pressure difference occurs. Therefore, since the capacitance C ₁ changes with respect to the temperature change but the capacitance C ₃ does not change, the capacitance change ΔC of the capacitive sensors 2A, 2B, and 2C is expressed by equation (9). Is the change in capacitance C ₁ . Thereby, also with the structure of the capacitive sensor 2A, 2B, 2C, power consumption can be reduced similarly to 1st Embodiment, and intermittent operation can be performed.

(Modification of Second Embodiment)

10 and 11 are for explaining a modification of the second embodiment of the capacitive sensor according to the present invention. In addition, unless otherwise indicated, the same structural part as 2nd Embodiment mentioned above is represented by the same code | symbol, and the description is abbreviate | omitted. In addition, the component part which is not shown in figure is made the same as that of 2nd Embodiment mentioned above.

The difference between the modification and the second embodiment is that the capacitive sensors 2D and 2E further include a new member.

10 is a side cross-sectional view of a capacitive sensor in a modification of the second embodiment of the present invention. As shown in FIG. 10, the capacitive sensor 2D includes a second member 40 provided below the lower member 30, and a second lower member installed below the second member 40. 50). The second member 40 is made of, for example, conductive single crystal silicon (low resistance silicon). In addition, the second lower member 50 is made of ceramics.

The diaphragm 41 is formed in the second member 40. On the upper surface of the diaphragm 41, a thin film-like protrusion 41a having electrical insulation is formed. On the lower surface of the lower member 30, a reference electrode 22 is provided at a position opposite to the upper surface of the diaphragm 41, and a capacitance C ₃ is formed between the upper surface of the diaphragm 41. The upper surface of the reference electrode 22 and the diaphragm 41 functions as a capacitor (capacitor). The left end of the diaphragm 41 is connected with a part (not shown) which comprises a part of the second member 40. This part is electrically connected to the diaphragm pad (terminal) P4 via the feed-through hole electrode H4. The left end of the reference electrode 22 is connected to the feed through hole electrode H3. The feed-through hole electrode H3 is electrically connected to the pad (terminal) P3 for thin film electrodes.

The gas A2 is sealed in the space S4 formed between the lower surface of the lower member 30 and the upper surface of the diaphragm 41 and sealed. In the space S5 formed between the upper surface of the second lower member 50 and the lower surface of the diaphragm 41, the same gas as the space S4, for example, the gas A2, is sealed.

Here, when the temperature measurement object, for example, the outside air temperature changes, since the gas with the same thermal expansion coefficient is enclosed in the space S4 and the space S5, the pressure of the space S4 and the pressure of the space S5 are sealed. There is no pressure difference between them. Therefore, as in the case of the second embodiment, since the capacitance C ₁ changes with respect to the temperature change but the capacitance C ₃ does not change, the capacitance change ΔC of the capacitive sensor 2D Is the change in capacitance C ₁ from equation (9) '.

In addition, as in the case shown in FIG. 8, the electrode forming the capacitance C ₃ between the reference electrode 22 is not limited to the diaphragm 41, but the fixed electrode formed on the second member 40. (Part) may be sufficient. The gas encapsulated in the space S4 and the space S5 is preferably an inert gas, but the gas A2 is preferably used. However, the gas A2 or other gas may be used.

11 is a side cross-sectional view showing another example of the capacitive sensor in the modification of the second embodiment of the present invention. In this modification, although the 2nd member 40 and the 2nd lower member 50 were provided, it is not limited to this. For example, as shown in FIG. 11, the capacitive sensor 2E may further be provided with the 2nd upper member 60 provided in the upper part of the 2nd member 40. As shown in FIG. That is, the capacitive sensor 2E includes a first capacitive sensor (not shown) including the member 10, the upper member 20, and the lower member 30, the second member 40, and the second. A second capacitive sensor (not shown) including the upper member 60 and the second lower member 50 is provided, and is constituted by two sensors having substantially the same configuration (structure).

In this case, the projection 41a is formed in the lower surface of the diaphragm 41, and the reference electrode 22 is provided in the position which opposes the lower surface of the diaphragm 41 in the upper surface of the 2nd lower member 50. As shown in FIG. The reference electrode 22 forms a capacitance C ₃ between the lower surface of the diaphragm 41. The lower surface of the reference electrode 22 and the diaphragm 41 functions as a capacitor (capacitor). The left end of the diaphragm 41 is connected with a part (not shown) which comprises a part of the second member 40. This part is electrically connected to the diaphragm pad (terminal) P4 via the feed-through hole electrode H4. The left end of the reference electrode 22 is connected to the feed through hole electrode H3. The feed-through hole electrode H3 is electrically connected to the pad (terminal) P3 for thin film electrodes.

The gas A2 is sealed in the space S4 formed between the lower surface of the second upper member 60 and the upper surface of the diaphragm 41 and sealed. In the space S5 formed between the upper surface of the second lower member 50 and the lower surface of the diaphragm 41, the same gas as the space S4, for example, the gas A2, is sealed.

Here, when the temperature measurement object, for example, the outside air temperature changes, the gas having the same thermal expansion coefficient is enclosed in the space S4 and the space S5, so that the pressure in the space S4 and the pressure in the space S5 are sealed. There is no pressure difference between them. Therefore, as in the case shown in FIG. 10, since the capacitance C ₁ changes with respect to the temperature change but the capacitance C ₃ does not change, the capacitance change ΔC of the capacitive sensor 2E is changed. Is the change in capacitance C ₁ from equation (9) '.

In addition, as in the case shown in FIG. 10, the electrode forming the capacitance C ₃ between the reference electrode 22 is not limited to the diaphragm 41, but the fixed electrode formed on the second member 40. (Part) may be sufficient. The gas encapsulated in the space S4 and the space S5 is preferably an inert gas, but the gas A2 is preferably used. However, the gas A2 or other gas may be used.

In this manner, according to the configurations of the capacitive sensors 2D and 2E, as in the first embodiment, power consumption can be reduced and intermittent operation can be performed.

(Third Embodiment)

12 to 14 are for explaining the third embodiment of the capacitive sensor according to the present invention. In addition, unless otherwise indicated, the same structural part as 1st Embodiment or 2nd Embodiment mentioned above is represented by the same code | symbol, and the description is abbreviate | omitted. In addition, the component part which is not shown in figure is made to be the same as 1st Embodiment or 2nd Embodiment mentioned above.

The difference between the third embodiment and the first or second embodiment is that the diaphragm 11 of the capacitive sensor 3 has a mesa shape 111.

In this application, a "mesa shape" means what was shape | molded in the trapezoid shape, and a pair of stool sides are parallel or substantially parallel.

It is a side sectional view of the capacitive sensor in 3rd Embodiment of this invention. As shown in FIG. 12, the diaphragm 11 has a mesa shape 111 on the lower surface thereof. In addition, the mesa shape 111 is not limited to the case where it has in the lower surface of the diaphragm 11. The diaphragm 11 may have a mesa shape in the surface which faces the space in which the high thermal expansion rate gas is enclosed among the base | substrate A1 and the base | substrate A2. In the present embodiment, since the gas A1 is a gas in a vacuum state and the gas A2 is an inert gas, the mesa is formed on the surface facing the space S2 in which the gas A2 is sealed, that is, on the lower surface of the diaphragm 11. It has a shape. In addition, in the other surface of the diaphragm 11 and in this embodiment, you may have a mesa shape also in the upper surface.

It is a top view explaining the shape of the diaphragm shown in FIG. As shown in FIG. 13, the mesa shape 111 is formed in the center part (center and its peripheral area | region) of the diaphragm 11 in planar view. In addition, the mesa shape horizontal (length in the X-axis direction in FIG. 13), vertical (length in the Y-axis direction in FIG. 13), and height (length in the Z-axis direction in FIG. 13) can be changed suitably.

Here, as in the first embodiment, when a pressure difference occurs between the pressure in the space S1 and the pressure in the space S2, the diaphragm 11 including the mesa shape 111 has a curved center portion (a concave). It becomes difficult to deform | transform into a mold, and it becomes easy to move a surface in parallel as it is. Therefore, the capacitance C ₁ and the capacitance C ₂ can be detected with high accuracy.

14 is a side cross-sectional view showing another example of the capacitive sensor in the third embodiment of the present invention. As shown in FIG. 14, similarly to the second embodiment, even when the capacitive sensor 3 includes the reference electrode 22, the diaphragm 11 is thermally expanded among the base A1 and the base A2. The mesa shape 111 is included in the surface which faces the space in which the gas with high rate is enclosed. Also in this case, as in the case shown in FIGS. 12 and 13, the capacitance C ₁ can be detected with high accuracy.

As described above, according to the capacitive sensor 3 of the present embodiment, the diaphragm 11 has a mesa shape 111 on a surface of the base A1 and the base A2 facing the space in which the base having the high thermal expansion coefficient is sealed. Has Here, as in the first embodiment, when a pressure difference occurs between the pressure in the space S1 and the pressure in the space S2, the diaphragm 11 having the mesa shape 111 has a curved center portion (concave shape). It becomes difficult to deform | transform into), and the surface becomes easy to move in parallel as it is. Therefore, the capacitance C ₁ can be detected with high accuracy. Thereby, the temperature of a measurement object can be measured more correctly.

(Fourth Embodiment)

15 to 17 are for explaining the fourth embodiment of the capacitive sensor according to the present invention. In addition, unless otherwise indicated, the same component part as 1st thru | or 3rd embodiment mentioned above is represented by the same code | symbol, and the description is abbreviate | omitted. In addition, the component part which is not shown in figure is made to be the same as 1st Embodiment-3rd Embodiment mentioned above.

The difference between the fourth embodiment and the first embodiment is that the capacitive sensors 4A and 4B use a silicon on insulator (SOI) substrate 10A as the member 10.

15 is a side cross-sectional view of a capacitive sensor in a fourth embodiment of the present invention. As shown in FIG. 15, the SOI substrate 10A includes a silicon layer 10a, an insulating layer 10b, and a base silicon layer 10c.

The silicon layer 10a is made of conductive silicon, for example. The diaphragm 11 and the electroconductive part 12 are formed in the silicon layer 10a. Here, by using the SOI substrate 10A including the silicon layer 10a designed to a predetermined thickness (length in the Z-axis direction in FIG. 15), thickness control is simplified, for example, during etching.

The insulating layer 10b is made of silicon oxide (SiO ₂ ), for example. The insulating layer 10b is interposed between the silicon layer 10a and the base silicon layer 10c. The insulating layer 10b functions as an insulating film which electrically insulates the silicon layer 10a and the base silicon layer 10c.

The base silicon layer 10c is made of conductive silicon, for example. In the base silicon layer 10c, the electrode portion 15 is formed at a position opposite to the diaphragm 11. Like the thin film electrode 31 in the first embodiment, the electrode portion 15 forms a capacitance C ₂ between the diaphragm 11. The electrode portion 15 and the diaphragm 11 function as a capacitor (capacitor).

In addition, the electrode part 15 is connected with the part (not shown) which comprises a part of base silicon layer 10c. This portion is electrically connected to the electrode pad (terminal) P3 provided on the lower surface of the lower member 30 through the feed-through hole electrode H3. In addition, through the formation of the feed-through hole electrode H3, through holes (not shown) are formed in the lower member 30, respectively, similarly to the first embodiment, and embedding film formation, plating method or wiring of the electrode material in the through holes. And the like.

FIG. 16 is a plan view of the electrode unit illustrated in FIG. 15. As shown in Fig. 16, the electrode portion 15 has a columnar hole 15a arranged in the transverse direction (X-axis direction in Fig. 16) and the longitudinal direction (Y-axis direction in Fig. 16) when viewed in plan. It has a plurality. These holes 15a are used when removing the insulating layer 10b. In general, when the insulating layer 10b is removed, for example, hydrofluoric acid vapor or buffered hydrofluoric acid (BHF) is used for etching. However, these materials rapidly spread in the vertical direction (Z-axis direction in FIGS. 15 and 16), but are difficult to spread in the horizontal direction (X-axis direction or Y-axis direction in FIGS. 15 and 16). . Therefore, by flowing in (flowing) through these holes 15a, the hydrofluoric acid vapor or the buffered hydrofluoric acid (BHF) can be diffused in the horizontal direction.

In addition, the shape of the opening part of each hole 15a is not limited to a regular hexagon, but may be circular, elliptical, rectangular, square, polygonal, or the like. However, the so-called honeycomb structure having a regular hexagonal opening is structurally stable. The number and size of the holes 15a can be appropriately changed in consideration of the surface area of the upper surface of the electrode portion 15 facing the diaphragm 11 and the insulating layer 10b in consideration of the removal rate.

17 is a side cross-sectional view showing another example of the capacitive sensor in the fourth embodiment of the present invention. As shown in FIG. 17, similarly to the second embodiment, even when the capacitive sensor 4B includes the reference electrode 22, the SOI substrate 10A is used as the member 10. Also in this case, as in the case shown in Fig. 15, by using the SOI substrate 10A including the silicon layer 10a designed to a predetermined thickness (length in the Z-axis direction in Fig. 17), for example, thickness control at the time of etching is performed. Becomes simpler.

As described above, according to the capacitive sensors 4A and 4B of the present embodiment, the SOI substrate 10A includes the silicon layer 10a, the base silicon layer 10c, and the silicon layer (10c) on which the diaphragm 11 is formed. And an insulating layer 10b interposed between 10a and the base silicon layer 10c. Here, by using the SOI substrate 10A including the silicon layer 10a designed to a predetermined thickness (length in the Z-axis direction in FIGS. 15 and 17), thickness control is simplified, for example, during etching. Thereby, the diaphragm 11 can be formed easily.

In addition, according to the capacitive sensor 4A of the present embodiment, the SOI substrate 10A includes a silicon layer 10a on which the diaphragm 11 is formed and a base silicon layer 10c on which the electrode portion 15 is formed. ) And an insulating layer 10b interposed between the silicon layer 10a and the base silicon layer 10c. Here, when the insulating layer 10b is removed, for example, hydrofluoric acid vapor or buffered hydrofluoric acid (BHF) is used for etching. However, these materials quickly spread in the vertical direction (Z-axis direction in FIGS. 12 and 13), but have a property that is difficult to spread in the horizontal direction (X-axis direction or Y-axis direction in FIGS. 15 and 16). Therefore, by flowing in (flowing) through these holes 15a, the hydrofluoric acid vapor and the buffered hydrofluoric acid (BHF) can be diffused in the horizontal direction. Thereby, the insulating layer 10b of the part corresponding to the diaphragm 11 can be removed clearly (completely).

(Fifth Embodiment)

18 to 21 are for explaining the fifth embodiment of the capacitive sensor according to the present invention. In addition, unless otherwise indicated, the same structural part as 1st Embodiment-4th Embodiment mentioned above is represented by the same code | symbol, and the description is abbreviate | omitted. In addition, the component part which is not shown in figure is made the same as that of 1st Embodiment-4th Embodiment mentioned above.

The difference between the fifth embodiment and the first embodiment is that the member 10 of the capacitive sensors 5A, 5B, or the SOI substrate 10A of the capacitive sensors 5C, 5D is a getter chamber S3. ) Is formed.

It is a side sectional view of the capacitive sensor in 5th Embodiment of this invention. As shown in FIG. 18, the getter chamber S3 communicating with the space S1 is formed in the member 10. The getter material 16 is housed in the getter chamber S3. The getter material 16 has a property of adsorbing (absorbing) a gas (gas). For example, a non-evaporable gas adsorption film, a commercial gas absorber, or the like can be used. Moreover, you may form the thin film electrode 21 on the lower surface of the upper member 20 using the material of a getter material.

As described above, the gas A1 enclosed in the space S1 is a gas in a vacuum state. Thereby, since the getter material 16 accommodated in the getter chamber S3 adsorbs the gas (gas) remaining in the space S1, the degree of vacuum of the gas A1 enclosed in the space S1 can be increased. have.

In particular, when bonding the member 10 and the upper member 20 using the anodic bonding method, oxygen (or oxygen ions) may be released from the upper member 20 made of glass or the like. In this case, the vacuum degree of the base A1 can be prevented from falling.

19 is a side cross-sectional view showing another example of the capacitive sensor in the fifth embodiment of the present invention. As shown in FIG. 19, the getter chamber S3 is formed in the member 10 also when the capacitive sensor 5B is equipped with the reference electrode 22 similarly to 2nd Embodiment. Also in this case, as in the case shown in FIG. 18, since the getter material 16 accommodated in the getter chamber S3 adsorbs the gas (gas) remaining in the space S1, it is enclosed in the space S1. The degree of vacuum of the gas A1 can be increased.

20 is a side cross-sectional view showing another example of the capacitive sensor in the fifth embodiment of the present invention. As shown in FIG. 20, the electrode part 15 is formed similarly to FIG. 15 shown in 4th Embodiment using the SOI board | substrate 10A as the member 10 with the capacitive sensor 5C. Also in this case, the getter chamber S3 is formed in the SOI substrate 10A, specifically, the base silicon layer 10c. In addition, since the getter chamber S3 is formed in the base silicon layer 10c thicker than the silicon layer 10a, it may be formed in the silicon layer 10a only because of the ease.

In the conductive portion 12, a communication hole 12a communicating with the space S1 and the getter chamber S3 is formed. In addition, the lower member 30 is provided with a through hole 32 for enclosing the base A2 in the space S2. The opening of the through hole 32 is sealed with a sealing material 33 after the SOI substrate 10A and the lower member 30 are bonded to each other and the base A2 is inserted into the space S2.

In addition, when the SOI substrate 10A and the lower member 30 are bonded together, air (air) is filled in the space S2. When moving to a place where the air pressure is low in this state, the atmosphere (air) is released from the space S2, so that it is possible to substitute the gas A2.

In this case as well, as shown in FIG. 18, since the getter material 16 accommodated in the getter chamber S3 adsorbs the gas (gas) remaining in the space S1, the gas enclosed in the space S1. The vacuum degree of (A1) can be raised.

21 is a side cross-sectional view showing another example of the capacitive sensor in the fifth embodiment of the present invention. As shown in FIG. 21, similar to FIG. 17 shown in the fourth embodiment, the capacitive sensor 5D includes the reference electrode 22 using the SOI substrate 10A as the member 10. Also in this case, the getter chamber S3 is formed in the SOI substrate 10A, specifically, the base silicon layer 10c. In addition, the getter chamber S3 may be formed in the silicon layer 10a as in the case described with reference to FIG. 20.

The lower member 30 is provided with a through hole 32 for enclosing the gas A2 in the space S2. The opening of the through hole 32 is sealed with a sealing material 33 after the SOI substrate 10A and the lower member 30 are bonded to each other and the base A2 is inserted into the space S2.

Also in this case, as in the case shown in FIG. 18, since the getter material 16 accommodated in the getter chamber S3 adsorbs the gas (gas) remaining in the space S1, it is enclosed in the space S1. The degree of vacuum of the gas A1 can be increased.

As described above, according to the capacitive sensors 5A, 5B, 5C, and 5D of the present embodiment, the getter material 16 is stored in the member 10 or the SOI substrate 10A and communicates with the space S1. The getter chamber S3 is formed, and the gas A1 enclosed in the space S1 is in a vacuum state. Thereby, since the getter material 16 accommodated in the getter chamber S3 adsorbs the gas (gas) remaining in the space S1, the degree of vacuum of the gas A1 enclosed in the space S1 can be increased. have.

In addition, the structure of each embodiment mentioned above may be combined or the some component part may be replaced. In addition, the structure of this invention is not limited only to embodiment mentioned above, You may change in various ways within the range which does not deviate from the summary of this invention.

[Industrial applicability]

The present invention can be applied to a technique for measuring temperature by intermittent operation.

1: capacitive sensor 10: absence
11: diaphragm 20: upper member
21: thin film electrode 30: lower member
31: thin film electrode A1: gas
A2: gas C ₁ : capacitance
C ₂ : capacitance S1: space
S2: space

Claims (9)

In the capacitive sensor that can detect the first capacitance and the second capacitance,
A first member having a conductive electrode plate having conductivity;
A first electrode forming said first capacitance between said electrode plate,
A second electrode forming the second capacitance between the electrode plate,
A second member provided to form a first space between one surface of the electrode plate;
A third member provided to form a second space between the other surface of the electrode plate
And,
A first gas is sealed in the first space, and a second gas having a different thermal expansion coefficient from the first gas is sealed in the second space. In the capacitive sensor that can detect the first capacitance and the second capacitance,
A first member having a conductive electrode plate having conductivity;
A first electrode forming said first capacitance between said electrode plate,
A second electrode for forming the second capacitance;
A second member provided to form a first space between one surface of the electrode plate;
A third member provided to form a second space between the other surface of the electrode plate
And,
A first gas is sealed in the first space, and a second gas having a different thermal expansion coefficient from the first gas is sealed in the second space. 3. The capacitive sensor according to claim 2, wherein the first member is conductive and an electrode portion is formed between the second electrode and the second capacitance. The capacitive sensor according to claim 2, further comprising a third electrode which forms the second capacitance between the second electrode and the second electrode. 3. The capacitive sensor according to claim 2, further comprising a fourth member having conductivity and having an electrode portion formed with the second electrode to form the second capacitance. The electrostatic capacitance according to any one of claims 1 to 5, wherein the electrode plate has a mesa shape on a surface of the first substrate and the second substrate facing a space in which a gas having a high thermal expansion coefficient is enclosed. Type sensor. The said 1st member is a 1st conductive layer in which the said electrode plate is formed, a 2nd conductive layer, and this 1st conductive layer, The said 2nd conductive layer is in any one of Claims 1-5. Capacitive sensor comprising an insulating layer interposed. The said 1st member is a 1st conductive layer in which the said electrode plate is formed, the 2nd conductive layer in which the said 2nd electrode is formed, and is interposed between this 1st conductive layer and this 2nd conductive layer. Capacitive sensor comprising an insulating layer to be. The said 1st member is formed with the 3rd space in which the getter material is accommodated and communicates with the said 1st space,
The first gas is in a vacuum state.

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